Lung cancer in connective tissue disease-associated interstitial lung disease: clinical features and impact on outcomes.

BACKGROUNDS

Lung cancer (LC) adversely impacts survival in patients with idiopathic pulmonary fibrosis. However, little is known about LC in patients with connective tissue disease-associated interstitial lung disease (CTD-ILD). The aim of this study was to evaluate the prevalence of and risk factors for LC in CTD-ILD, and the clinical characteristics and survival of CTD-ILD patients with LC.

METHODS

We conducted a single-center, retrospective review of patients with CTD-ILD from 2003 to 2016. Patients with pathologically diagnosed LC were identified. The prevalence, risk factors, and clinical features of LC and the impact of LC on CTD-ILD patient outcomes were observed.

RESULTS

Of 266 patients with CTD-ILD, 24 (9.0%) had LC. CTD-ILD with LC was more likely in patients who were older, male, and smokers; had rheumatoid arthritis, a usual interstitial pneumonia pattern, emphysema on chest computed tomography scan, and lower diffusing capacity of the lung carbon monoxide (DLco)% predicted; and were not receiving immunosuppressive therapy. Multivariate analysis indicated that the presence of emphysema [odds ratio (OR), 8.473; 95% confidence interval (CI), 2.241-32.033] and nonuse of immunosuppressive therapy (OR, 8.111; 95% CI, 2.457-26.775) were independent risk factors for LC. CTD-ILD patients with LC had significantly worse survival than patients without LC (10-year survival rate: 28.5% 81.8%, P<0.001).

CONCLUSIONS

LC is associated with the presence of emphysema and nonuse of immunosuppressive therapy, and contributes to increased mortality in patients with CTD-ILD.